A nutrition surveillance survey was conducted in June 1990
in four poor rural counties of Hubei Province, China, that
included 25 villages and 3,564 children, to determine early
feeding practices and the nutrition status of preschool children.
Data were collected through interviews, anthropometric
measurements, analysis of haemoglobin values, and physical
examinations. More than 90% of the infants under 6 months of age
were being breast-fed, as were approximately 75% of those 12
months old and 26% of those 24 months old. A trend to introducing
solid foods into children's diets at younger ages appeared to
have occurred between 1984 and 1988; only 15% of the children ate
solid food at 6 months of age and 58% at 12 months in 1984,
compared with 23% and 78% respectively in 1988. The children's
anthropometric measurements were comparable to international
standards for the first months of life, and then weight-forage
and height-for-age Z scores deviated negatively. Physical
examinations suggested that several micronutrient deficiencies
might be present The data also indicated that during a time of
sweeping economic changes and expanded health care availability,
breast-feeding was maintained, food was introduced into the diets
of children at younger ages, and acute malnutrition was not
common.

Introduction

The economic status of the People's Republic of China has
improved significantly over the past 30 years, with a change in
the growth rate of the gross national product (GNP) from 4.1% for
1965-1980 to 8.2% for 1980-1989 [1]. National indicators of
nutrition status indicate significant improvements in infant
mortality, mortality under the age of five years, and life
expectancy (tables 1 and 2) [2]. At the same time, the country
has increased the breadth and number of health and nutrition
programmes that benefit children, such as greater access to safe
drinking water, improved sewage disposal, increased immunization
coverage, and mass campaigns against parasitic diseases [3].
Growth studies from urban areas reported a significant increase
in the mean weight of older children between the 1950s and the
1980s but little change in preschool children [4].

Information about the health and nutrition status of children
living in the rural areas of China is limited. One method to
obtain such information is through surveillance programmes that
target populations at the greatest risk for nutritional problems
[5]. These programmes have the advantage of being able to
determine how nutrition status changes over time and can be used
to evaluate various interventions [6]. Such a survey was
conducted in rural Hubei province as part of the national
nutrition surveillance programme to determine if the nutritional
patterns of rural children had changed during the 1980s.

Methods

In June 1990 the Ministry of Health conducted a
cross-sectional survey in four counties of Hubei province, a
central location for heavy industry, transportation, and
communication, located on the Yangtze River. The population of
the province in the years preceding the survey was estimated to
be about 35 million.

The counties selected for the study have a
geographic distribution of hilly and plain areas and were chosen
because they were considered economically disadvantaged and
therefore at greater risk for poor nutrition status. They had an
annual per capita income between US$40 and US$100 in 1989. More
than 90% of the households had electricity, and the main sources
of drinking water were wells and rivers. Ninety-five per cent of
the children in the area went to school at five years of age, and
more than 90% of those under six years were up to date with their
immunizations. The major diseases in the preschool children were
respiratory and gastrointestinal infections; infant mortality was
less than 50 per 1,000.

Health officials from each county selected two
townships to participate in the survey on the basis of the
criteria of accessibility, willingness to participate, and having
at least 400 children under six years of age. From these eight
townships the largest 25 villages were selected as sample
villages, and from these villages 3,564 children (at least 95% of
those who met the criterion of being under six years of age,
based on regional birth and health records) were recruited and
participated in the survey. Another 17] also met the age
criterion but were not included in the analysis because missing
data prevented the computation of ages or standardized
anthropometric values.

Socio-economic and medical information for each
child was obtained from a parent through a series of 36
questions, including the parent's education and occupation, the
child's birth order, birthweight, history of acute or chronic
diseases, how long the child was breast-fed, and the timing and
types of solid foods that were introduced. A physical examination
was performed for each child to identify signs and symptoms
associated with protein-energy malnutrition and deficiencies of
thiamine, riboflavin, ascorbic acid, vitamin A, vitamin D, and
iron.

The percentage of children who were currently
being breast-fed was determined. For those who had stopped
breast-feeding, the age of weaning was recorded retrospectively
to determine whether there had been a change in the length of
breast-feeding. The proportions of children who were breast-fed
for 12, 24, and 36 months were compared across each age cohort
using chi-square analysis.

The parents were asked at what age rice, egg,
vegetables, fruit, soya beans, meat, and other foods were
introduced into the children's diets. From these data, the age at
which the first of these foods was introduced was determined for
each child. The average age at which the first solid food was
introduced was compared across each age cohort by analysis of
variance, and the proportions of children consuming solid food at
6, 12, 18, and 24 months of age were compared by chi-square
analysis. The pattern for introducing each food into the diet was
also determined, and the proportions of children eating the
various foods at 6, 12, 18, and 24 months were compared by
chi-square analysis.

Anthropometric measurements were taken by four
teams of investigators who were trained as recommended by the
United Nations [7]. The children wore sleeveless shirts, shorts,
and no shoes. Children were weighed with platform-beam scales,
calibrated daily, and the weights were recorded to the nearest 25
g; infants were weighed either on an infant scale or in a
container that had a known weight. Length and height measurements
were recorded to the nearest 0.1 cm. Children over three years of
age were measured with a stadiometer; those under three were
measured in a recumbent position using an infant measuring board
with a fixed headboard and movable footboard. Blood was obtained
by finger prick, and haemoglobin concentrations were determined
by the cyanomethaemoglobin method [8].

Data were entered using dBASE III software
(Ashton-Tate, Culver City, Calif.). The weight and height
information was converted to Z-score values for weight for age
(WAZ), height for age (HAZ), and weight for height (WHZ) based on
the NCHS/CDC/ WHO standards using the EPINUT version 1.00
software (US Centers for Disease Control, Atlanta, Ga.). The data
were then transferred to a Hewlett Packard minicomputer, and the
statistical analyses were conducted using the SAS software
programme [9]

The mean growth patterns of the children were
compared with the NCHS/CDC/WHO standards [10]. The percentages of
children with scores more than two standard deviations below the
mean were determined by six-month age groups up to two years of
age, and then by one-year age groups up to six.

A total of 1,977 boys and 1,587 girls were
involved in the study. Their age and sex distributions are shown
in figure 1. Children under one year old represented 18.3% of the
sample, and one-year-olds 22.8%. Children two, three, four, and
five years old constituted 19.4%, 18.0%, 15.1%, and 6.4% of the
sample respectively. There was a prominent yearly periodicity in
the occurrence of ages, with the number of births increasing
toward the month of January and decreasing afterward for each
year. In the samples, 1.7% were twins, 45.1% were first born, and
39.8% were second born. Of the 3,564 children, 5.5% had a low
birthweight. A majority of the parents had graduated either from
middle school (45.7% of fathers, 39.8% of mothers) or from high
school (27.6%, 13.2%).

Breast-feeding

At the time of the study, more than 90% of the
children under six months old were being breast-fed (fig. 2), as
were 75% of the one-year-olds and 26% of the two-year-olds.
Breast-feeding continued until three years of age for 3% of
children. Retrospective data about when children had stopped
breast-feeding indicated no significant difference for those two
to five years old.

Figure 3 shows the ages at which solid food was
introduced. A significant temporal change occurred between 1984
and 1988 with respect to earlier introduction of solid foods. For
example, 25% of the children born in 1987-1988 were consuming
solid food at six months of age, compared with 15% of those born
in 1984-1985 (X2 = 14.0, p < .001). Similarly, 80% of those
born in 1987-1988 were consuming solid food at 12 months,
compared with 58% of those born in 1984-1985 (X2 = 58.3, p <
.001).

There was a significant difference in the age
at which various foods were introduced (X2 = 455, p < .001),
but the order of foods did not vary among the age groups. Figure
4 shows the timing of the introduction of various foods into the
diets of children who were two years old at the time of the
survey. Rice was almost always introduced first; 60% of the
children were consuming rice by the age of 12 months. The next
two foods were usually eggs and vegetables, followed by soya
beans and fruit; 50%, 35%, 27%, and 20% of the children
respectively were consuming these foods by 12 months. Meat tended
to be introduced last, with 20% consuming it by 12 months.

Low birthweight ( < 2,500 g) was reported in
5.5% of the children. The mean WAZ and WHZ values for both boys
and girls under six months were greater than zero, and the mean
HAZ value was near zero. The scores did not indicate any
consistent difference between the growth of boys and girls for
any of the age groups studied compared with the reference
standards.

After six months of age, the mean WAZ
fluctuated around-1.00 SD for both boys and girls (fig. 5). The
percentage of children with a WAZ below -2.00 SD was lowest
during the first year of life (6.1%) and greatest at 12-17 months
(32.6%) (fig. 6).

The mean HAZ was comparable to the NCHS median
within the first few months of life. At 12 months it was about
-1.00, and by 36 months it was about -2.00. The percentage of
children below-2.00 SD for HAZ increased from 9% for children
under one year old to 44% for those 18-23 months old. However,
two-year-olds showed a decline in the percentage with low HAZ
(30.5%), but this increased in each age group until five years of
age (43%).

The mean WHZ values started above the NCHS
standard mean until about 65 cm in length (fig. 7). They remained
between the NCHS mean and -1.00 SD for children between two and
five years of age. Those 12-17 months had the greatest percentage
with WHZ values below -2.00 (9.2%), compared with less than 2%
for those three and four years old.

The proportion of children with haemoglobin
concentrations less than 11 g/dl was greatest in infants 611
months old (42%). After one year of age the proportion of
children who had low haemoglobin values decreased (fig. 8).
Haemoglobin levels were positively correlated with the time foods
were introduced into the diet. The correlation coefficients were
significant with probability below .001 for rice (r=.17), eggs
(r=.17), fruit (r=.20), vegetables (r=.20), soya beans (r=.22),
protein (r=.20), and other foods (r=.20). Children who had
consumed milk had slightly higher haemoglobins than those who had
not (11.7 ± 1.3 vs. 11.1 ± 1.4; p < .05). Haemoglobin was
not correlated with WAZ, HAZ, or WHZ values nor with the presence
of a recent infection. It was not associated with the level of
education for mothers or fathers.

Signs and symptoms of nutritional deficiency

Clinical impressions of rickets were recorded
in 6.4% of the children. Children suspected of having rickets
represented 4.0% of the total sample, moderate disease 2.2%, and
severe 0.2%. Riboflavin deficiency was suspected in 4.1 %,
vitamin C deficiency in 0.7%, and vitamin A deficiency in 0.3%.
Other suspected deficiencies were thiamine (0.2%) and iodine (0 1
% ).

Discussion

Our findings indicate that there were, indeed,
changes in the feeding patterns of preschool children in the area
surveyed during a time in which sweeping changes in economic
policies and substantial economic growth were occurring in China.
During that same time, public health interventions were
increased, with expanded primary care coverage and extended
nutrition education.

Breast-feeding was the predominant
infant-feeding method until about six months of age, with only
25% of mothers reporting that solid food was introduced by this
age. However, between 1984 and 1989 rice and other foods were
being given to children at younger ages. Nonetheless,
breast-feeding continued to supply nutrients to nearly 75% of the
children at 12 months of age, and breast-feeding was common in
one- and two-year-olds. Extending breast-feeding beyond the first
year of life has been associated with greater anthropometric
measurements even after controlling for the introduction of other
foods, infections, and various socio-economic factors [11]. The
breast-feeding rates were greater than have been reported for
most Asian settings (in rural or urban areas), where indications
are that between 60% and 80% of infants are breast-fed for six
months [12].

It appears that the initiation and duration of
breast-feeding were greater in rural Hubei than in other areas of
China. However, no national data are available on the proportion
of infants who are breast-fed for 12 months. Our findings are
consistent with a series of studies suggesting that
breast-feeding rates in China are higher in rural areas and
decrease with greater urbanization [13-15]. For example, in
Shanghai 32.3% of infants were reported to be breast-feeding for
six months, compared with 73.7% in the suburbs [15]. According to
one national study, 60.3% of infants in rural areas breast-feed
for six months, compared with 34.4% in urban areas [13]. However,
the surveyed areas of Hubei province had the greatest rate, with
94.7% of the children 12-47 months old being breast-fed for at
least six months, and 61.7% for at least 12 months.

The differences in these results may also be
associated with attitudinal differences in the populations. A
greater percentage of women in the suburbs (94.2%) believed that
breast-feeding is best for the child, compared with 87.8% of
women living in Shanghai [15]. Other attitudinal differences
associated with increased amounts of breast milk (a proxy for
successful breast-feeding) included believing that nothing was
better than breast milk and that extended breast-feeding was
appropriate [15]. Not having had a difficult labour and not
having a premature infant were also associated with greater
production of breast milk [15].

The health education campaigns in Hubei
province did not focus on breast-feeding, since the practice is
ubiquitous and the supply of breast-milk substitutes is limited.
These may be two reasons why no change in breast-feeding rates
were seen despite the country's increased prosperity.

Exclusive breast-feeding stops when solid
foods, soups, and liquids other than breast milk are given to
infants. Preceding the current survey, the nutrition surveillance
programme in Hubei put an emphasis on the earlier introduction of
nutrient-rich foods that would increase the intake of protein,
zinc, and vitamin C. The programme may have contributed to the
significant change that was demonstrated in this study. However,
the earlier introduction of solid foods could occur for many
other reasons that were not determined in the present analysis,
such as increased financial resources and improved crop
production [1].

An analysis of Malaysian data reported that
digit preferences are present when women retrospectively report
the duration that they breast-fed their children [16]. Similarly,
preferences for 6,12, 18, 24, 30, and 36 months were observed in
the current study. Although the retrospective nature of the
current data could be considered a limitation, the data from
Malaysia suggest that the time frame used for retrospective data
had less effect on the reliability of measurements than
socioeconomic status or ethnicity, both of which were fairly
equal in the present study.

We believe that solid food is being introduced
earlier to children. What has not been measured is the amount
being introduced and consumed. It is also recognized that solid
food is being given later than current international
recommendations; in the cohort born between 1987 and 1988, more
than 75% of the children were reported to have been first given
solid foods after six months of age.

The positive association between haemoglobin
values and the eating of solid food may be a marker for one of
the benefits of earlier introduction of solid food. In a more
global approach, this association illustrates how improved
economic status improves nutrition status, since families with
more resources are able to offer infants solid food earlier and
may have access to more informal sources of health information.
This would be a reason why haemoglobin values were greater in
children who received milk other than breast milk, since these
would be children whose families were more able to afford milk
products. Without additional information, however, it is
difficult to determine what factors are associated with the
higher haemoglobins.

The infants in rural Hubei province were
slightly heavier than the reference standards. The strongest
evidence for this is the WAZ and HAZ values recorded for children
under three months old; the mean Z scores of both groups were
positive. Additional support is the small percentage of infants
with birthweights under 2,500 g. Although the low-birth-weight
rate reported in this study would include only survivors, the
weights of infants one to three months old support the view that
these Chinese children were larger than the reference standards.
It was only after the age at which solid foods are recommended to
be introduced that the children in our study showed a negative
deviation from the reference growth standards. This deviation
could occur either because of the later introduction of solid
food or because the growth of breast-fed infants may actually
differ from that of bottle-fed infants in terms of pattern,
velocity, and tissue composition [17-20].

National reference growth data for China,
collected in 1985 from a representative sample of 175,290
middle-income children from four northern provinces and six
southern provinces, suggest that the weights of infants in the
first month of life are also greater than international
references [21, 22]. The data for the children from the four poor
counties in Hubei province were comparable with the national
growth data for the first six months of life, but thereafter they
had lower weight and height values for their ages. Their
decreased growth rate after 12 months of age could be the result
of such things as being fed solid foods at an older age, less
overall intake, or an increased frequency of infectious diseases,
including those due to parasites.

The results of two separate analyses indicate
that growth rates in China are highest in children from urban
areas, lower in children from the suburbs, and even lower in
children from rural areas [21, 22]. Compared with children in
other rural areas with a mid-level socioeconomic status, the boys
in Hubei province had lower mean weight and height values after
one year of age, and the girls after six months.

There has been a significant temporal trend of
increased growth rates among Chinese children during the past two
decades. The rates for older children are now comparable to
NCHS/WHO standards, especially for stature [4]. Data from several
countries indicate that changing environmental conditions have
significantly increased the growth of children. Between 1963 and
1967 the heights of southern Chinese children in Hong Kong were
comparable to international standards, and deviations were
strongly associated with socio-economic status [23]. The average
heights of Thai children also increased between ]962 and 1975
[24]. Furthermore, a secular trend of increased growth was
reported for Japanese children who immigrated to the United
States, which may be due to increased intake of protein and fat
[25].

In conclusion, the dietary and growth patterns
of children in rural Hubei may be changing. Although much of this
change may be due to economic and health care policies, the
persistence of breast-feeding and the introduction of solid foods
into the diets of infants at younger ages may be having equally
important effects.

Acknowledgements

We extend our appreciation to Goubing Zhang and
Gouching Yi for their assistance with the research design and
data-collection procedures. We are grateful for the help of Xiao
Fang, Xiao Yeng Liu, Ann - Xing Wang, and Liping He in data
collection. We also acknowledge Kathleen Jaegers for her careful
editing and typing of the final manuscript.

References

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2. UNICEF. The state of the world's children
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3. World Bank. World development report 1990.
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7. United Nations, National Household Survey
Capability Programme, Co-operation for Development and
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the nutritional status of young children in household surveys.
New York: United Nations, 1986.

14. Meehan KF. Breast feeding in an urban
district in Shanghai, People's Republic of China: a descriptive
study of feeding patterns and hospital practices as they relate
to breast feeding. J Trop Pediatr 1990;36:75-9.